@ what temp?

If it's legal, wear it. You'll swim faster.

Don't know that I totally agree with that. Yes, you will swim faster, but I wore it for water temps at 75 and overheated. Thought I was going to have to take off the wetsuit and leave it in the latke. If you need it for security than wear it, but if you're confident that you can do the distance I would think about how much advantage it would give you.

I tend to agree with you. I'm a decent swimmer, not the fastest but I'm comfortable in the water.

I'm leaning towards having a full sleeved one for <65 and having a sleeveless for 65-75 degrees. I've worn a full sleeve for 70 degrees and was VERY glad it was only a sprint and I was out in 20 minutes. Any longer and I would have broiled I think.

However, what I said is still technically correct, if it's legal, wear one and you will swim faster

thank you for validating my thoughts, i believe i will go sleeveless

If you swim 30 seconds faster, and the fight with the wetsuit for 30 seconds in transition, have you gained anything?

For your first tri, if you don't need the wetsuit for temps, I wouldn't wear it.  KISS. (Keep it simple, silly)

I'm guessing you've never used a wetsuit. It might takes about five seconds to take off and you can do most of it as you're running from the water to your T1 area.

Kind of interesting, but I do pay attention to some people's race logs, and most wetsuit races have longer T1's by about a minute.  I haven't done any complete analysis, but this is what I seem to notice. 

While that's probably a valid observation, just looking at race results won't paint the whole picture.  Some transition areas are 100 yards away from the water, some can be up to a quarter of a mile away.  That will affect your T1 times, and not necessarily reflect taking off a wetsuit as the culprit for the time discrepancy.  I agree above, you're talking about probably 5 seconds of extra time if you've practiced taking it off.  There's plenty of youtube videos that show you the proper way to strip a wetsuit that won't seriously affect your T1 time.

I've never used a wetsuit in a triathlon, no.   I've worn both shorties and fulls for diving and waterskiing.   If you can get one off in the heat of the moment in your first tri in 5 seconds.... kudos to you.